[Bob Lincoln]

You have a couple of options, depending on how much length is left on the stud.

One is to fold back the carpeting and drill from the inside, and put a new bolt in, being careful to seal the body so there are no exhaust fumes. JB Weld epoxy is good for that. The downside to this is you are drilling blindly, either up or down, so you risk hitting something with the drill bit.

The way I did it was to buy a double-female thread hex standoff, screw it onto the remaining stud, and run a bolt up into it from the bottom. You can find these parts at a hardware store. You just have to know the thread size, which you can get if you take the good nut in and have them gauge it. It's a metric thread, I think it might be M8 x 1.25mm. This repair worked fine.

Be sure to use anti-seize compound on every fastener when you reinstall.

 

[blake_mcguire]

There's pretty much nothing left underneath of the old stud. The car has no interior at the moment, so I guess drilling is the way to go

 

[Bob Lincoln]

OK, so you probably want stainless steel M8 x 1.25 x 50mm or longer. Be sure to seal around it with epoxy or something firm, not RTV.

 

[soloflite]

Grind the rest of the bolt down. Pull the back seat out. Go back underneath and drill a hole out where you ground down the bolt. Drop one in from where the rear seat is. Seal it up. I had to do the same on my 89.

 

[Bob Lincoln]

You don't actually have to pull the seat out, just fold it down. The bolt is mounted right under where the seatback meets the cargo floor.

 

[soloflite]

You have to pull the seat. There is a metal brace that needs to come out, and it's bolted underneath the seat Bob. so yes it does have to come out in order to drop the new bolt.

 

[Bob Lincoln]

I can't see that. The bolt goes in at the leading edge of the cargo floorpan.

 

[soloflite]

do it, then you'll see it. I've "PHYSICALLY" done it..

 

[TM1963]

I broke one off also. Here are a couple of photos from the (passenger) side - top of the bolt. 1988. Seats were still in the car.

Before:

After:

I drilled this out and replaced with stainless bolt/lockwashers.

 

[soloflite]

Correct, however you are missing the metal plate that goes there to make that a flat surface. In order to get that metal plate out, you have to remove the seat. I'll get pics of mine.

See the black plate just in front of the spare tire well, that needs removed to drop the new bolt, this is on my 86, my 89 that I did it to also had that plate.

 

[Bob Lincoln]

I was able to remove that black plate just by folding the seats down and lifting the carpet.

 

[TM1963]

I was also able to remove the plate (in my 88) without removing the seats... however - the OP stated 'the car has no interior at the moment'... so if that statement also means - no rear seats are in the car, it will be a bit easier to access - however he plans to tackle the problem

 

[blake_mcguire]

Yes, there's no interior in the car so it's a non-issue, but I also agree that you don't need to take out the seats to remove the black plate.

 

[blake_mcguire]

So what do you guys do to keep the bolt from turning when you're doing things up underneath? I've just started on this fix today. I missed when I was drilling, so the hole is just behind the old bolt, but it seems to me that it should work anyway.

 

[Bob Lincoln]

If you don't have an assistant, then use a lockwasher before the nut goes on. That way, you can hold the end of the bolt underneath and tighten the nut until the lockwasher contacts the underside of the floorpan and bites in. The bolt will then not turn, and you can tighten the nut.